1) Field of the Invention
The present invention relates to cargo handling and, more specifically, to an adjustable system and associated method for facilitating the handling of cargo in a cargo carrier.
2) Description of Related Art
Existing trailers of transfer trucks that are sometimes used with cargo delivered to airport cargo handling terminals typically have floors fitted with roller systems for supporting pallets of cargo for easy movement in and out of the trailer. One such prior system is the Retract-A-Roll(copyright) system supplied by Ancra International, Inc. of Erlanger, Ky. These rollers systems are also used in aircraft. However, their use in truck trailers presents many problems. Truck trailers are dirty and are subject to rough use, thus, subjecting the roller systems to wear and damage. Also the roller systems are heavy, for example, sometimes adding up to 1,800 pounds or more of weight per trailer. Thus, the inclusion of a roller system in a trailer reduces the amount of freight or cargo that may be carried. This is particularly undesirable when the trailer is used to carry cargo not intended for delivery to an airline. The roller systems are also expensive. However, truckers who wish to deliver goods to air cargo services are often required to use trailers having these roller systems.
Thus, there exists a need for a cargo handling system that facilitates the movement of cargo into and out of a cargo carrier. The cargo handling system should be suited for use in harsh conditions, such as in truck trailers. Additionally, the system should not be unnecessarily heavy or costly to install or maintain.
The present invention provides an adjustable system and an associated method for handling cargo in a cargo carrier. Adjustable low friction strips facilitate loading, unloading, and transit of the cargo. The strips are lightweight in comparison to conventional roller systems, and perform well in dirty or rough conditions. The strips can easily be replaced if worn. Further, the strips can be selectively adjusted between operative and non-operative positions.
In one embodiment of the invention, the system includes a plurality of the strips extending longitudinally from a loading aperture of the cargo carrier. Each strip has a relatively lower coefficient of friction than a floor of the carrier. In the operative position, each strip extends from the floor of the cargo carrier so that the cargo can be slid upon and supported by the strips. In the non-operative position, the strips are adjusted relative to the floor so that the cargo is at least partially supported by the floor. According to one aspect of the invention, the strips are rotatably adjustable between the operative and non-operative positions. For example, each strip can be rotatably supported by a hinge and configured to rotate from a position in which the strip extends from the floor to a position in which the strip is disposed in a groove in the floor. The strips can be hinged individually or can be mounted on a frame that can be rotated from the floor about 90 degrees. According to another aspect, the floor defines a plurality of grooves for receiving the strips, and each strip is slidably adjustable relative to the floor from the operative position, in which the strips extend above the floor, to the non-operative position, in which the strips are retracted into the grooves. Each strip can be supported by a respective groove so that slidably adjusting the strip longitudinally adjusts the strip in a transverse direction perpendicular to the floor between the operative and non-operative positions. The strips and/or the respective grooves define guides that include at least one ramped portion and at least one flat portion for the range of motion of the strips. For example, each strip can define a plurality of ramped surfaces that engage correspondingly ramped surfaces of the floor. Alternatively, protrusions and corresponding notches can be provided on the strips and sidewalls of the grooves so that the strips slidably engage the sidewalls by the notches, which are ramp shaped and receive the protrusions so that longitudinal adjustment of each strip correspondingly extends and retracts the strip relative to the floor. According to yet another aspect, a bladder can be provided in the grooves under the strip and configured to be inflated and deflated with a fluid so that the strip can be extended or retracted relative to the floor. In each embodiment, a linkage can connect the strips so that they move in unison between the operative and non-operative positions. Additionally, each strip can include a replaceable low friction portion that is releasably connected to a structural portion of the strip.
The present invention also provides a method of handling cargo in a cargo carrier. The method includes providing the low friction strips of material for supporting the cargo during unloading or loading and during transit, the strips having a relatively lower coefficient of friction than a floor of the cargo carrier. The strips are selectively adjusted between the operative and a non-operative positions. According to one aspect, the strips are adjusted by rotating, for example, by adjusting a linkage that connects the strips and rotating the strips at least about 180 degrees about an axis parallel to the floor. Alternatively, the strips can be connected by a frame that is rotated about 90 degrees about an axis parallel to the floor. According to another aspect of the invention, the strips are adjusted by sliding the strips relative to the floor in a longitudinal direction between the operative position, in which the strips extend above the floor, and the non-operative position, in which the strips are retracted into the grooves. Alternatively, the strips can be adjusted by selectively inflating and deflating a plurality of bladders with fluid. The bladders are disposed in grooves and support the strips so that inflating the bladders extends the strips from the grooves and to the operative position and deflating the bladders retracts the strips into the grooves and to the non-operative position.